Gac Ma (Johnson South) is a reef in the Truong Sa (Spratly) Islands claimed by Vietnam. China has illegally occupied the reef since 1988 after an unequal battle during which 64 Vietnamese soldiers were killed, many of them unarmed.

In 1989 China built an embankment on the reef and has since 2014 carried out reclamation work to expand the usable surface area to 11 hectares.

China has built a military and radar base, a lighthouse and a small harbor on the newly-claimed area.

Vietnam has repeatedly opposed China’s reclamation and construction works on Gac Ma as well as other reefs it is occupying in Truong Sa.

Such works are a “serious violation of Vietnam’s sovereignty,” and “complicates the situation and escalates tension,” according to the Vietnamese foreign ministry.